题目大意:给定一棵 N 个点的树,边有边权,定义"线树"为一个图,其中图的顶点是原树中的边,原树中两条有公共端点的边对应在线图中存在一条边,边权为树中两条边的边权和,求线图的最小生成树的代价是多少. 题解: 对于树中的一个顶点来说,假设有 M 条边以该顶点为一个端点,那么这 M 条边对应到线图中的顶点必须要求能够构成一个联通块.另外,可以发现这个问题的解决和其他顶点无关,即:对于树上每个顶点来说,构成了一个子问题.因此,考虑一个贪心策略,即:每次用边权最小的那条边和其他所有边相连,这样…
题解: solution Code: A. Apple Business #include<cstdio> #include<algorithm> #include<vector> using namespace std; typedef long long ll; const int N=100010; int Case,len[N],n,m,i,mx,a[N],size[N],tmp[N];ll ans; vector<ll>v[N],f[N]; str…
B. Balanced Diet 思路:把每一块选C个产生的价值记录下来,然后从小到大枚举C. #include<bits/stdc++.h> using namespace std; ; typedef long long ll; vector<int> G[maxn]; int l[maxn], a[maxn], b[maxn]; ll dp[maxn]; bool cmp(int a, int b) { return a > b; } int main() { std:…
ZOJ Problem Set - 3946 Highway Project Time Limit: 2 Seconds Memory Limit: 65536 KB Edward, the emperor of the Marjar Empire, wants to build some bidirectional highways so that he can reach other cities from the capital as fast as possible. Thus…
The Lucky Week Time Limit: 2 Seconds Memory Limit: 65536 KB Edward, the headmaster of the Marjar University, is very busy every day and always forgets the date. There was one day Edward suddenly found that if Monday was the 1st, 11th or 21st day…
People Counting Time Limit: 2 Seconds Memory Limit: 65536 KB In a BG (dinner gathering) for ZJU ICPC team, the coaches wanted to count the number of people present at the BG. They did that by having the waitress take a photo for them. Everyone w…
Defuse the Bomb Time Limit: 2 Seconds Memory Limit: 65536 KB The bomb is about to explode! Please defuse it as soon as possible! There is a display showing a number from 1 to 4 on the bomb. Besides this, there are 4 buttons under the display. Ea…
提交链接 http://codeforces.com/gym/100781/submit Description: Ada, Bertrand and Charles often argue over which TV shows to watch, and to avoid some of their fights they have finally decided to buy a video tape recorder. This fabulous, new device can reco…
